Adaptive seat belt tensioning system

ABSTRACT

An adaptive seat belt system ( 10 ) for an automotive vehicle ( 12 ) is provided. The system ( 10 ) includes a seat belt ( 16 ) extensible about an occupant ( 42 ) of a seat system ( 14 ). A seat belt tension sensor ( 18 ) is coupled to the seat belt ( 16 ) and generates a seat belt tension signal. A seat belt actuator ( 20 ) is mechanically coupled to the seat belt ( 16 ) and adjusts tension of the seat belt ( 16 ). A controller ( 26 ) is electrically coupled to the tensioner sensor ( 18 ) and the actuator ( 20 ). The controller ( 26 ) generates a seat belt tension adjustment signal in response to the seat belt tension signal and adjusts tension of the seat belt ( 16 ) in response to the seat belt tension adjustment signal. A method for performing the same is also provided.

RELATED APPLICATION

[0001] The present invention is related to U.S. Provisional Applicationserial No. 60/253,317 (Attorney Docket numbers V200-0745, V200-0864,V200-0023, and V200-0866) entitled “Electronically controlled fourcorner real-time seat adjustment system”, “Electronically controlledadaptive seat adjustment system with occupant detection”,“Electronically controlled adaptive seat adjustment system”, and“Dynamic seat controller” filed together as on Nov. 27, 2001 andincorporated by reference herein.

TECHNICAL FIELD

[0002] The present invention relates generally to automotive vehiclesystems, and more particularly, to a method and apparatus for adaptivelyadjusting seat belt tension during vehicle operation.

BACKGROUND OF THE INVENTION

[0003] Active seat systems experience real-time seat movement due tovarious automotive vehicle maneuvers. An occupant of an active seatsystem may be subject to real-time seat belt forces that vary inresponse to range and type of movement of the occupant in the seatsystem. The varying seat belt forces can become unpleasant to theoccupant.

[0004] Traditional seat systems are capable of being translated in afore and aft direction or in an upward and downward direction relativeto a vehicle frame. An active seat system incorporates additionalmobility by incorporating 4-point actuation, such that the seat systemis also capable of tilting in multiple directions about a center point.The center point is located at approximately center between 4-actuators,each actuator is located at an outer base corner of the active seatsystem.

[0005] The all-encompassing mobility of the active seat system is usedto aid in counteracting imputed forces on an occupant during vehiclemaneuvering. For example, as the vehicle is performing a right turn, theactive seat system tilts to the right to offset side forces experiencedby an occupant of the vehicle. Instead of the occupant leaning into theturn or physically resisting the lateral forces while in the turn, aportion of the lateral forces are distributed into the active seatsystem. Similar, active seat system movement is experienced during othervehicle maneuvers including accelerations and braking.

[0006] An occupant wearing a seat belt is normally fixed within a seatsystem. The seat belt is rigidly mounted directly to a vehicle frame, orto a seat frame, which in turn is rigidly mounted to the vehicle frame.The movements of the active seat system during vehicle maneuvering cancause belt pressure on the occupant, which may be discomforting. As theseat system tilts and presses an occupant against the seat belt, anyslack in the seat belt decreases and tension of the seat belt increases.The increase in seat belt tension causes the undesirable discomfortexperienced by the occupant.

[0007] The increase in seat belt tension typically occurs and is mostprevalent when the active seat system moves in a forward or upwarddirection, thereby pressing the occupant tighter against the seat belt.

[0008] Multiple energy management systems and vehicle collision systemshave been introduced in the past for absorbing energy during acollision, whereby seat belt tension is adjusted during a collisionevent. These prior systems use collision sensors, which are utilized indetermining probability of a collision. In response to the probabilityof the collision and other vehicle parameters and occupantcharacteristics, a seat belt pretensioner is activated and seat belttension is adjusted accordingly. Many pretensioning devices are one-timeuse devices in that they are triggered during or immediately proceedinga collision and are not reusable. The past systems are incapable ofcounteracting varying seat belt tensions experienced during normaloperating conditions, which do not involve collision prediction andinjury prevention.

[0009] It would therefore be desirable to develop a technique foradjusting seat belt tension during vehicle maneuvers as to preventundesirable pressure or discomfort on a vehicle occupant.

SUMMARY OF THE INVENTION

[0010] The present invention provides a method and apparatus foradaptively adjusting seat belt tension during vehicle operation. Anadaptive seat belt system for an automotive vehicle is provided. Thesystem includes a seat belt extensible about an occupant of a seatsystem. A seat belt tension sensor is coupled to the seat belt andgenerates a seat belt tension signal. A seat belt actuator ismechanically coupled to the seat belt and adjusts tension of the seatbelt. A controller is electrically coupled to the seat belt tensionsensor and the seat belt actuator. The controller generates a seat belttension adjustment signal in response to the seat belt tension signaland adjusts tension of the seat belt in response to the seat belttension adjustment signal. A method for performing the same is alsoprovided.

[0011] One of several advantages of the present invention is the abilityto adjust seat belt tension, during vehicle operation, to compensate forseat system movement. The ability to adjust seat belt tension decreasesthe potential for seat belt discomfort due to seat system movement,especially for active seat systems.

[0012] Another advantage of the present invention is that in adjustingseat belt tension, vehicle dynamics, occupant characteristics, and seatsystem position are considered, thereby, providing seat belt tensiondetermination system for various operating conditions and occupantcharacteristics. Thus, the system can potentially provide increasedoccupant safety by maintaining adequate seat belt tension on a vehicleoccupant.

[0013] Furthermore, the present invention unlike traditional seat beltsystems that utilize single use pretensioning devices, the presentinvention provides active seat belt tension adjustment that is capableof increasing or decreasing seat belt tension continuously duringvarious vehicle operating conditions.

[0014] The present invention itself, together with attendant advantages,will be best understood by reference to the following detaileddescription, taken in conjunction with the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] For a more complete understanding of this invention referenceshould now be had to the embodiments illustrated in greater detail inthe accompanying figures and described below by way of examples of theinvention wherein:

[0016]FIG. 1 is a block diagrammatic view of an adaptive seat beltsystem for an automotive vehicle in accordance with an embodiment of thepresent invention;

[0017]FIG. 2 is a front view of an occupied seat system utilizing theadaptive seat belt system in accordance with an embodiment of thepresent invention; and

[0018]FIG. 3 is a logic flow diagram illustrating a method of adaptivelyadjusting tension of a seat belt within the automotive vehicle inaccordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0019] In each of the following figures, the same reference numerals areused to refer to the same components. While the present invention isdescribed with respect to a method and apparatus for adaptivelyadjusting seat belt tension during vehicle operation, the presentinvention may be adapted to be used in various systems including:automotive vehicle systems, control systems, hybrid-electric vehiclesystems, or other applications utilizing an active or adjustable seatsystem.

[0020] In the following description, various operating parameters andcomponents are described for one constructed embodiment. These specificparameters and components are included as examples and are not meant tobe limiting.

[0021] Referring now to FIG. 1, a block diagrammatic view of an adaptiveseat belt system 10 for an automotive vehicle 12 in accordance with anembodiment of the present invention is shown. The system 10 includes oneor more seat systems 14, each seat system 14 having a corresponding seatbelt 16. Each seat belt 16 is coupled to a seat belt tension sensor 18and a seat belt actuator 20. The seat systems 14 are active seatsystems, in that they are capable of being actuated by multiple seatsystem actuators 22, in multiple directions relative to a vehicle frame24. A controller 26 is electrically coupled to the tension sensors 18,the belt actuators 20, and the seat system actuators 22 as well as toother vehicle components such as a vehicles dynamic sensor 28 and anoccupant characteristic sensor 30. As the vehicle 12 is operated thetension sensors 18, the dynamics sensor 28, and the occupantcharacteristic sensor 30 are monitored by the controller 26. Duringvehicle dynamics as the seat systems 14 are actuated in variousdirections the controller 26 generates a seat belt tension adjustmentsignal in response to vehicle dynamics, occupant characteristics, andcurrent tension of the seat belts 16 to adjust seat belt tension via thebelt actuators 20.

[0022] The tension sensor 18 may be a load cell, a strain gage, or othertension sensor known in the art. The tension sensor 18 may includemultiple tension sensors that are located in an isolated portion of theseat belt 16 or may be distributed to various locations on the seat belt16 to measure distributed tension levels throughout length of the seatbelt 16.

[0023] The belt actuators 20 perform the function of a seat beltretractor as well as additional functions to compensate for seat belttension fluctuations due to movement of the seat system 14. The beltactuators 20 are active unlike a seat belt retractor in that the beltactuators 20 are capable of retracting and extending the seat beltthroughout vehicle operation and may continuously perform adjustmentstherein.

[0024] Seat system actuators 22 are similar to seat system actuatorsknown in the art. The seat system actuators include directional positionsensors 32. The directional position sensors 32 are used to determinethe position of the seat system 14 axially in X, Y, and Z directions aswell as rotationally about the X, Y, and Z axis. The directionalposition sensors 32 may be of encoder style, infrared style,potentiometer style, or of other style known in the art.

[0025] The controller 26 is preferably microprocessor based such as acomputer having a central processing unit, memory (RAM and/or ROM), andassociated input and output buses. The controller 26 may be a portion ofa central vehicle main control unit, an interactive vehicle dynamicsmodule, a restraints control module, a main safety controller, or astand-alone controller.

[0026] The vehicle dynamics sensor 28 may be a single sensor or aconglomerate of various vehicle sensors including: a brake sensor, athrottle sensor, an inertial sensor, a steering sensor, a suspensionsensor, a vehicle inertial sensor, a wheel speed sensor, a vehicle speedsensor, accelerometers, a pedal sensor, a seat track sensor, a steeringcolumn sensor, or other vehicle sensor. The inertial sensor may allowthe system 10 to determine roll, pitch, and yaw of the vehicle 12 or ofa vehicle component in the X, Y, and Z directions. The accelerometersmay be remote accelerometers located near the outer contact surfaces ofthe vehicle 12 as to measure immediate collision accelerations or localaccelerometers located at various internal vehicle locations as tomeasure internal accelerations. The above sensors may be usedindividually, separately, or in conjunction with each other. They mayalso be used for multiple purposes for example in generating the seatbelt tension adjustment signal or in generating other various signals.

[0027] The occupant characteristic sensor 30 may also be a single sensoror a conglomerate of various vehicle sensors including sensors such as:an occupant position sensor, a seat belt sensor, an occupantcharacteristic sensor, accelerometers, or other various sensors known inthe art. The occupant characteristic sensor 30 generates an occupantcharacteristic signal that may include weight of an occupant, height ofan occupant, position of an occupant relative to the seat system 14, orother various occupant characteristics, known in the art.

[0028] Referring now to FIG. 2, a front view of an occupied seat system40 utilizing the adaptive seat belt system 10 in accordance with anembodiment of the present invention, is shown. The occupied seat system40 includes an occupant 42 seat belted into the seat system 14. The seatbelt 16 is extensible about the occupant 42 and is anchored, by a seatbelt anchor 43, to the frame 24, on a first end 44. The seat belt 16 isguided over a lap 46 of the occupant 42, to a seat belt buckle 48, whichis clasped to a receptacle 50 and also anchored to the frame 24. Theseat belt 16 is then guided over a shoulder 52 of the occupant 42through a seat belt adjuster 54, mounted to a vehicle body 56, andfinally to the tension sensor 18 and the belt actuator 20 at a secondend 55, which are also mounted to the vehicle body 56. Of course, theseat belt anchor 43, the seat belt adjuster 54, the tension sensor 18,and the belt actuator 20 may be mounted at various locations within thevehicle 12 and may also be actuated and repositioned in conjunction withpositioning of the seat system 14. For example, as the seat system 14 isactuated in a forward direction the controller 26 may compensate bymoving the belt actuator 20 in a forward direction.

[0029] The seat system 14 may be actuated, as stated above, in variousdirections, represented by arrows 60. During vehicle operation as theseat system 14 causes tension within the seat belt 16 to change overtime, the system 10 adjusts seat belt tension by retracting or extendingthe length of the seat belt 16, via the actuator 20, as represented byarrows 62. The seat belt adjustments may be performed continuouslyduring vehicle operation including the following vehicle operatingconditions and situations: vehicle steering, vehicle accelerations,vehicle braking, a vehicle collision, an apprehension of a vehiclecollision, or various other vehicle operating conditions and situations.

[0030] Referring now to FIGS. 1 and 2, the seat system 14 may alsoinclude seat bolsters 70 and seat bolster actuators 71. Seat bolsters 70may respond both in the y and/or z directions in response to vehicledynamics, via the seat bolster actuators 71. The seat bolster actuatorsmay include electrical motors, mechanical linkages, pneumatics, or otherdevices known in the art. Also in determining seat bolster positioningforce sensors may be used, current may be monitored of an electricmotor, or other position sensing device or method may be used.

[0031] The controller 26 when compensating for active seat bolstermovement, may adjust seat belt tension with actuator 20 in response tochange in occupant and/or seat orientation, at least a portion of whichmay be measured by actuator sensor 18. For example, when the vehicle 12is experiencing lateral acceleration from a turning maneuver, theoccupant 42 may experience side forces in the y axis direction. The seatbolsters 70, in response to the side forces respond inward accordinglyand return to a corresponding seat bolster base position following thecompletion of the turning maneuver. During the event, seat belt tensionexperienced by the occupant 42 in seat belt 16 increases and may inhibitproper movement of the active seat system 14 causing occupant 42 toexperience uncomfortable seat belt tension. Controller 26 compensatesfor the increased seat belt tension by relieving seat belt tensionthrough partial release or extension of seat belt 16 as represented byarrows 62. Upon conclusion of the vehicle turning maneuver, seatbolsters 70 return outward to the corresponding seat bolster baseposition accordingly and seat belt tension also returns to acorresponding seat belt base position by retraction of seat belt 16represented by arrows 62.

[0032] Referring now to FIG. 3, a logic flow diagram illustrating amethod of adaptively adjusting tension of a seat belt within theautomotive vehicle in accordance with an embodiment of the presentinvention, is shown.

[0033] In step 100, the dynamics sensor 28 generates a vehicle dynamicssignal in response to a dynamic parameter of the vehicle 12. The dynamicparameter may be generated due to any of the above stated conditions orsituations. The dynamic parameter may, as in the following example,correspond to vehicle deceleration, in which case the dynamic parameterincludes a deceleration value. The deceleration example is furtherdescribed throughout the following steps and is meant only to aid in theunderstanding of the present invention, multiple other scenarios arealso contemplated.

[0034] In step 102, the occupant characteristic sensor 30 determines anoccupant characteristic and generates an occupant characteristic signal.The occupant 42 has multiple characteristics including: being male orfemale, being of various size and shape, and being in various seatedpositions on the seat system 14, for example. The occupantcharacteristic sensor generates the occupant characteristic signal inresponse to one or more of the stated characteristics.

[0035] In step 103, the directional position sensors 32 generate seatposition signals. The seat position signals correspond to the abovestated potential axial and rotational existing positions of the seatsystem 14.

[0036] In step 104, the controller 26 generates a seat positionadjustment signal and may also generate a seat bolster adjustment signalin response to the vehicle dynamics signal, the occupant characteristicsignal, and the seat position signals.

[0037] In step 106, the seat system actuators 22 adjust the position ofthe seat system 14 and the seat bolsters 70 in response to the seatposition adjustment signal and the seat bolster adjustment signal,respectively.

[0038] In step 110, the tension sensor 18 determines tension of the seatbelt 16 and generates a seat belt tension signal. The tension of theseat belt 16 may fluctuate depending upon various conditions andsituations. For example, as the vehicle 12 is decelerating such asduring braking the seat belt tension is increasing. When the vehicle 12is steered around a curve the seat system 14 is tilted in a left or in aright direction to compensate for lateral forces experienced by theoccupant 42, thereby causing seat belt tension to fluctuate. The tensionsensor 18 may generate the seat belt tension signal in response to thefluctuations in seat belt tension or may continuously generate the seatbelt tension signal.

[0039] In step 112, the controller 26 generates the seat belt tensionadjustment signal in response to a reference seat belt tension. Thecontroller 26 compares an existing seat belt tension, from the seat belttension signal, with the reference seat belt tension and adjusts theexisting seat belt tension to approximately equal the reference seatbelt tension. In a preferred embodiment of the present invention, thereference seat belt tension is approximately equal to tension of theseat belt 16 when the occupant 42 latches the buckle 48 to thereceptacle 50 or some time soon thereafter, to allow for adjustment ofthe seat belt 16. Of course, the reference seat belt tension may also beset at other times during other conditions or situations.

[0040] In step 116, the belt actuator 20 receives the seat belt tensionadjustment signal and performs generally one of three functions:retracts the seat belt 16 to increase seat belt tension, extends theseat belt 16 to decrease seat belt tension, or maintains length of theseat belt 16 to maintain a current seat belt tension. Upon adjustingtension of the seat belt 16, the controller 26 may return to step 110 toconfirm that the existing seat belt tension is approximately equal tothe reference seat belt tension, return to step 100 to reevaluatepositions of the seat system 14 and the bolsters 70, or a combinationthereof.

[0041] The above-described steps are meant to be an illustrativeexample, the steps may be performed synchronously or in a differentorder depending upon the application.

[0042] The present invention therefore provides a seat belt tensionadjustment system that is active in that seat belt tension is capable ofbeing adjusted continuously throughout vehicle operation in variousconditions and situations. The present invention provides a seat beltsystem that compensates for active seat system movements and istherefore more desirable to a vehicle occupant. The present inventionalso potentially increases safety of a vehicle by maintaining anappropriate seat belt tension for a given occupant in a particulardriving condition and situation.

[0043] The above-described apparatus, to one skilled in the art, iscapable of being adapted for various purposes and is not limited to thefollowing systems: automotive vehicle systems, control systems,hybrid-electric vehicle systems, or other applications utilizing anactive or adjustable seat system. The above-described invention may alsobe varied without deviating from the spirit and scope of the inventionas contemplated by the following claims.

What is claimed is:
 1. An adaptive seat belt system for an automotivevehicle comprising: a seat belt extensible about an occupant of a seatsystem; a seat belt tension sensor coupled to said seat belt andgenerating a seat belt tension signal; a seat belt actuator mechanicallycoupled to said seat belt for adjusting tension of said seat belt; and acontroller electrically coupled to said seat belt tension sensor andsaid seat belt actuator, said controller generating a seat belt tensionadjustment signal in response to said seat belt tension signal andadjusting tension of said seat belt in response to said seat belttension adjustment signal.
 2. A seat belt system as in claim 1 furthercomprising: one or more seat system actuators mechanically coupled tosaid seat system and electrically coupled to said controller; and avehicle dynamic sensor electrically coupled to said controller andgenerating a vehicle dynamic signal; said controller adjusting positionof said seat system relative to a vehicle frame in response to saidvehicle dynamic signal.
 3. A system as in claim 1 further comprising:one or more seat system actuators mechanically coupled to said seatsystem and electrically coupled to said controller; and an occupantcharacteristic sensor electrically coupled to said controller andgenerating an occupant characteristic signal; said controller adjustingposition of said seat system in response to said occupant characteristicsignal.
 4. A system as in claim 3 wherein said occupant characteristicsignal comprising at least one of the following: a weight value, aheight value, or position indication of said occupant relative to a seatsystem.
 5. A system as in claim 1 further comprising: at least one seatbolster; at least one seat bolster actuator coupled to said at least oneseat bolster; and a vehicle dynamic sensor electrically coupled to saidcontroller and generating a vehicle dynamic signal; said controllerelectrically coupled to said at least one seat bolster actuator andadjusting position of said at least one seat bolster in response to saidvehicle dynamic signal.
 6. A system as in claim 1 further comprising: atleast one seat bolster; at least one seat bolster actuator coupled tosaid at least one seat bolster; and an occupant characteristic sensorelectrically coupled to said controller and generating an occupantcharacteristic signal; said controller electrically coupled to said atleast one seat bolster actuator and adjusting position of said at leastone seat bolster in response to said occupant characteristic signal. 7.A system as in claim 1 wherein said controller compares said seat belttension signal with a reference seat belt tension and adjusts tension ofsaid seat belt to approximately equal said reference seat belt tension.8. An adaptive seat belt system for an automotive vehicle comprising: aseat belt extensible about an occupant of a seat system; a seat belttension sensor coupled to said seat belt and generating a seat belttension signal; a seat belt actuator mechanically coupled to said seatbelt and adjusting tension of said seat belt; one or more seat systemactuators mechanically coupled to said seat system; one or moredirectional position sensors electrically coupled to said one or moreseat system actuators and generating one or more seat position signals;and a controller electrically coupled to said seat belt tensioner, saidseat belt actuator, said one or more seat system actuators, and said oneor more directional position sensors, said controller generating a seatbelt tension adjustment signal in response to said seat belt tensionsignal and adjusting tension of said seat belt in response to said seatbelt tension adjustment signal.
 9. A seat belt system as in claim 8further comprising: a vehicle dynamic sensor electrically coupled tosaid controller and generating a vehicle dynamic signal; said controlleradjusting position of said seat system relative to a vehicle frame andin response to said vehicle dynamic signal.
 10. A system as in claim 8further comprising: an occupant characteristic sensor electricallycoupled to said controller and generating an occupant characteristicsignal; said controller adjusting position of said seat system relativeto a vehicle frame and in response to said occupant characteristicsignal.
 11. A system as in claim 10 wherein said occupant characteristicsignal comprising at least one of the following: a weight value, aheight value, or position indication of said occupant relative to a seatsystem.
 12. A system as in claim 8 further comprising: at least one seatbolster; at least one seat bolster actuator coupled to said at least oneseat bolster; and a vehicle dynamic sensor electrically coupled to saidcontroller and generating a vehicle dynamic signal; said controllerelectrically coupled to said at least one seat bolster actuator andadjusting position of said at least one seat bolster in response to saidvehicle dynamic signal.
 13. A system as in claim 8 further comprising:at least one seat bolster; at least one seat bolster actuator coupled tosaid at least one seat bolster; and an occupant characteristic sensorelectrically coupled to said controller and generating an occupantcharacteristic signal; said controller electrically coupled to said atleast one seat bolster actuator and adjusting position of said at leastone seat bolster in response to said occupant characteristic signal. 14.A system as in claim 8 wherein said controller compares said seat belttension signal with a reference seat belt tension and adjusts tension ofsaid seat belt to approximately equal said reference seat belt tension.15. A method for adaptively adjusting tension of a seat belt within anautomotive vehicle comprising: determining tension of a seat belt andgenerating a seat belt tension signal; generating a seat belt tensionadjustment signal in response to said seat belt tension signal; andadjusting tension of said seat belt in response to said seat belttension adjustment signal.
 16. A method as in claim 15 furthercomprising: comparing said seat belt tension signal with a referenceseat belt tension; and adjusting seat belt tension to approximatelyequal said reference seat belt tension.
 17. A method as in claim 15further comprising: generating a vehicle dynamics signal; adjusting seatposition in response to said vehicle dynamics signal; generating saidseat belt tension signal upon adjusting seat position; and generatingsaid seat belt tension adjustment signal in response to said seat belttension signal.
 18. A method as in claim 15 further comprising:generating an occupant characteristic signal; adjusting seat position inresponse to said occupant characteristic signal; generating said seatbelt tension signal upon adjusting seat position; and generating saidseat belt tension adjustment signal in response to said seat belttension signal.
 19. A method as in claim 15 further comprising:generating a vehicle dynamics signal; adjusting position of at least oneseat bolster in response to said vehicle dynamics signal; generatingsaid seat belt tension signal upon adjusting position of said at leastone seat bolster; and generating said seat belt tension adjustmentsignal in response to said seat belt tension signal.
 20. A method as inclaim 15 further comprising: generating a occupant characteristicsignal; adjusting position of at least one seat bolster in response tosaid occupant characteristic signal; generating said seat belt tensionsignal upon adjusting position of said at least one seat bolster; andgenerating said seat belt tension adjustment signal in response to saidseat belt tension signal.